Heat exchanger and method for fabricating the same

ABSTRACT

A heat exchanger comprises a base portion and a plurality of fins. The fins are disposed in parallel on the base portion. Each fin has an upper margin far away from the base portion. The distance between each upper margin and the base portion is substantially gradually reduced along a first direction. The upper margins sunken to form at least one groove. The groove extends along a second direction which intersects with the first direction. The structure of the heat exchanger can prevent cutting waste filling in the passages between fins and thus block of passages can be avoided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 101109183 filed in Taiwan, R.O.C. on Mar. 16, 2012, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The disclosure relates to a heat exchanger and method for fabricating the heat exchanger, and more particularly to a heat exchanger having a plurality of fins and method for fabricating the heat exchanger.

2. Description of the Related Art

A heat dissipation module for a cabinet server often uses air-cooling heat dissipation mode. The operation of air-cooling heat dissipation is to set heat dissipation fins on various heat sources and to set corresponding heat dissipation fans in the casing of the cabinet server. The heat convection forced by the heat dissipation fans can dissipate heat generated by the heat sources. In this heat dissipation manner, the environmental temperature of the casing is very high because after the airflow brought by the heat dissipation fans takes way heat, the environmental temperature will be increased. Therefore, during the heat dissipation for the cabinet server, the directions for dissipating heat needed to be uniformed so that a cold channel and a hot channel are formed to control the environmental temperature. If environmental temperature of equipment room is not well controlled, it is very difficult to decrease the temperature of the cabinet server. With area of the equipment room getting larger, the density of servers is getting much greater. The design and management of environmental temperature, cold channel and hot channel become increasingly complicated.

The liquid-cooling heat dissipation module provides another manner for dissipating heat. The liquid-cooling heat dissipation module does not use air to decrease temperature, and thus it will not have the shortcomings of the air-cooling heat dissipation. The liquid-cooling heat dissipation module comprises a cooling device and a cooling pipe connecting the cooling device. The cooling device and the cooling pipe are disposed on the cabinet. The cooling pipe is connected to a heat exchanger for a heat source. The heat exchanger comprises an upper casing and a base. A plurality of heat dissipation fins are disposed in parallel on the base. Multiple passages are formed between fins. The upper casing is assembled to the fins and covers the fins. The fins are set in a chamber formed by the upper casing and the base. A cooling liquid provided by the cooling device flows to the heat exchanger through the cooling pipe. In the heat exchanger, the cooling liquid flows through passages between fins and performs heat exchange with fins so as to take away heat absorbed by the fins.

However, height errors of the fins may occur when fabricating the fins. If the fins are too high, a gap between the base and the upper casing may be formed by interference of fins and the upper casing. In this case, inferior-quality products may occur due to the difficulty in sealing the base and the upper casing. In the other hand, if the fins are too low, a gap between the fins and the upper casing may be formed. In this case, cooling liquid may flow through the gap between the fins and the upper casing and does not sufficiently contact with the fins. Thus, the heat dissipation efficiency is influenced.

SUMMARY OF THE INVENTION

In one aspect, a method for fabricating a heat exchanger is disclosed. The method comprises providing a substrate. The substrate comprises a base portion and a processing portion on the base portion. A thickness of the processing portion is substantially gradually reduced along a first direction. At least one groove is formed on the processing portion. The at least one groove extends along a second direction which intersects with the first direction. A plurality of fins is skived in parallel on the base portion. The plurality of fins extends along the first direction. The groove passes through each fin. Each fin having an upper margin far away from the base portion. A distance between each upper margin and the bottom surface is substantially gradually reduced along the first direction. The plurality of fins is milled along the first direction. The maximum distance between the upper margin and a bottom surface of the base portion is smaller than or equal to a preset value.

In another aspect, a heat exchanger is disclosed. The heat exchanger comprises a base portion having a bottom surface and a plurality of fins disposed on a side of the base portion far away from the bottom surface. Each fin has an upper margin far away from the base portion. A distance between each upper margin and the bottom surface is substantially gradually reduced along a first direction. The upper margins sunken to form at least one groove, and the groove extends along a second direction which intersects with the first direction.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from the detailed description given herein below for illustration only, and thus are not limitative of the present disclosure, and wherein:

FIG. 1 is a flowchart for fabricating a heat exchanger according to an embodiment of the disclosure;

FIGS. 2A-7B show a fabricating process for a heat exchanger according to an embodiment of the disclosure;

FIG. 7C shows a fabricating process for a heat exchanger according to another embodiment of the disclosure; and

FIG. 8 is a structure illustration of a heat exchanger according to another embodiment of the disclosure.

DETAILED DESCRIPTION

In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.

The detailed characteristics and advantages of the disclosure are described in the following embodiments in details, the techniques of the disclosure can be easily understood and embodied by a person of average skill in the art, and the related objects and advantages of the disclosure can be easily understood by a person of average skill in the art by referring to the contents, the claims and the accompanying drawings disclosed in the specifications.

FIG. 1 is a flowchart for fabricating a heat exchanger according to an embodiment. In this embodiment, the heat exchanger may be used in a liquid cooling heat dissipation module which is disposed in a cabinet server. The heat exchanger dissipates the heat generated from heat sources in the cabinet server. The fabricating flow for the heat exchanger will be described as below.

Firstly, a substrate is provided. The substrate comprises a base portion and a processing portion on the base portion. The processing portion has an upper surface and the base portion has a bottom surface. That is, the upper surface is opposite to the bottom surface. The distance between the upper surface and the bottom surface is substantially gradually reduced along a first direction (step S1).

Next, at least one groove is formed on the upper surface along a second direction which interacts with the first direction (step S2).

The processing portion is skived to form a plurality of fins in parallel standing on the base portion. The fins extend along the first direction and the at least one groove passes through each fin. Each fin has an upper margin far away from the base portion. Furthermore, the distance between each upper margin and the bottom surface is substantially reduced along the first direction (step S3).

The fins are cut along the first direction. The maximum distance between the upper margins and the bottom surface is smaller than or equal to a preset value (step S4).

An upper casing is provided. The upper casing comprises an accommodating space. A liquid input and a liquid output are connected to the accommodating space (step S5).

The upper casing is assembled to the base portion. The fins are set in the accommodating space. Furthermore, the liquid input and the liquid output are set at the two opposite ends of the fins (step S6).

FIGS. 2A-7B show a fabricating process for a heat exchanger according to an embodiment. The detailed process is set forth as below.

Firstly, as shown in FIG. 2A, the substrate 100 is provided. The substrate 100 can be made of but not limited to metal, such as aluminium alloy. The substrate 100 can be made by aluminum extrusion, but the disclosure is not limited this way. The substrate 100 comprises a base portion 110 and a processing portion 120 on the base portion 110. As shown in FIG. 2B, the processing portion 120 has an upper surface 121 and the base portion 110 has a bottom surface 111. The upper surface 121 is opposite to the bottom surface 111. The thickness of the processing portion 120 is substantially gradually reduced along a first direction d1. In this embodiment, the distance between the upper surface 121 and the bottom surface 111 is substantially reduced along a first direction d1. For example, the upper surface 121 is a slope. As shown in FIG. 2B, the distance between the upper surface of right end of the slope and the bottom surface 111 is represented by H11, and the distance between the upper surface of left end of the slope and the bottom surface 111 is represented by H12. The distance H11 is larger than the distance H12. It should be noted that the term “substantially reduce” means a reducing trend along the first direction d1. In other words, if there is irregular fluctuation on a segment of the upper surface 121, it is also regarded that the distance between the upper surface 1210 and the bottom surface 111 is substantially reduced along the first direction.

Next, as shown in FIGS. 3A and 3B, at least one groove 122 are formed on the upper surface 121 along a second direction d2 which interacts with the first direction by process such as milling. In the embodiment shown by FIGS. 3A and 3B, the number of the grooves is for example two, but the number is not limited by this embodiment. Furthermore, the second direction d2 is substantially perpendicular to the first direction d1. Here the term “substantially perpendicular” means that the angle intersected by the first direction d1 and the second direction d2 is approximately a right angle under appropriate processing errors. In other embodiments, the substrate 100 and the grooves 122 can be fabricated together by way of aluminum extrusion.

The processing portion 120 is skived to form a plurality of fins 130 in parallel standing on the base portion 110. More particularly, as shown in FIGS. 4A-4C, firstly the processing portion 120 is cut by using a knife 30 along the cutting direction d3 so as to form a fin 130. The cutting direction d3 and the upper surface 121 form an acute angle θ, as shown by FIG. 4B. Then, the fin 130 is bended to stand on the base portion 110, as shown by FIG. 4C. A plurality of fins 130 are formed in the same way as the above. The distance h2 between the upper margins of the curved fins 130 and the bottom surface 111 is greater than the distance h1 between the upper surface 121 to the bottom surface 111. Furthermore, the smaller the acute angle θ is, cutting direction d3 and the upper surface 121 form an acute angle θ, the larger the distance h2 between the upper margin and the bottom surface 111 will be (i.e., the height of the fins will be larger). As a result, persons skilled in the art would obtain an expected height of fins 130 by adjusting the acute angle θ.

As shown by FIG. 5A, the fins 130 extend along the first direction d1. The grooves 122 extend along the second direct and pass by each fin 130. As shown in FIG. 5B, two adjacent fins 130 have a passage 132 therebetween. Each fin 130 has an upper margin 131 far away from the base portion 110. Each upper margin 131 is a part of the upper surface 121 and has part of the structural feature of the upper surface 121. As a result, distance between each upper margin 131 and the bottom surface 111 is substantially reduced along the first direction d1. For example, as shown in FIG. 5C, the distance H21 between the right upper margin 131 and the bottom surface 111 is larger than the distance H22 between the left upper margin 131 and the bottom surface 111. In this embodiment, the upper surface 121 before milling and curving process is a slope, and thus after the milling and curving process, the upper margins 131 of fins 130 form an oblique line. However, the shape of the upper margin 131 is not limited by this embodiment. For example, if the upper surface 121 before milling and curving process is a step plane, the upper margin 131 s of fins 130 may form approximately a broken line, as shown by FIG. 8.

With reference to FIG. 6A, the fins 130 are milled by a knife 32 (e.g., milling cutter) along the first direction to make the maximum distance between the upper margin 131 and the bottom surface 111 is smaller than or equal to a preset value h3, where the value h3 may be determined according to different requirements. In this way, the height of the fins 130 can be controlled within a certain range to avoid interference with other elements (e.g. the upper casing 200 in FIG. 7A) when assembly.

As described above, the distance between the upper margin 131 and the bottom surface 111 is substantially gradually reduced along the first direction d1. Each groove 122 extends along the second direction d2 and is formed on the upper margin 131. In this case, when milling the fins 130 along the first direction d1 by using the knife 32, the milling waste is easily removed and thus does not stuff the passage 132 between two fins 130.

Then, with reference to FIG. 7A, an upper casing 200 is provided. The upper casing 200 comprises an accommodating space 201. A liquid input 210 and a liquid output 220 are connected to the accommodating space 201.

The upper casing 200 is assembled to the base portion 110. The fins 130 are set in the accommodating space 201. As shown in FIG. 7B, the liquid input 210 and the liquid output 220 are at the opposite two ends of the fins 130. The upper casing 210 completely covers the base portion 110, but the disclosure is not limited this way. For example, as shown in FIG. 7C, the upper casing 200 can be assembled on the base portion 110 and partly covers the base portion 110.

In this embodiment, the upper casing 200 may be assembled to the base portion 110 by a solder, but the disclosure is not limited this way. When assembling the upper casing 200 to the base portion 110, the distance H23 between the upper margin 131 near the liquid input 210 and the bottom surface 111 is larger than the distance H22 between the upper margin 131 near the liquid output 220 and the bottom surface 111. More particularly, the upper margin 131 near the liquid input 210 is substantially attached to the upper casing 200.

With reference to FIGS. 7A and 7B, the heat exchanger 10 may be fabricated by the above mentioned process. The heat exchanger 10 comprises the base portion 110 and a plurality of fins 130. The base portion 110 has the bottom surface 111. The fins 130 are disposed in parallel on the side far away from the bottom surface 111. Each fin 130 has an upper margin 131 far away from the base portion 110. Furthermore, the distance between each upper margin 131 and the bottom surface 111 is substantially gradually reduced along the first direction. The upper margins 131 sunken to form at least one groove 122. Each groove 122 extends along the second direction d2 which intersects with the first direction d1. The first direction d1 is substantially perpendicular to the second direction d2. Furthermore, the upper margins may from approximately an oblique line or a broken line, but the disclosure is not limited this way.

In addition, in this embodiment, the heat exchanger 10 further includes an upper casing 200. The upper casing 200 comprises an accommodating space 201. A liquid input 210 and a liquid output 220 are connected to the accommodating space 201. The upper casing 200 is assembled to the base portion 110. The fins 130 are in the accommodating space 201. The liquid input 210 and the liquid output 220 are set at two opposite ends of the fins 130. The distance H23 between the upper margin 131 near the liquid input 210 and the bottom surface 111 is larger than the distance H22 between the upper margin 131 near the liquid output 220 and the bottom surface 111. The upper margin 131 near the liquid input 210 is substantially attached to the upper casing 200. In this case, when cooling liquid flows into the accommodating space 201 from the liquid input 210, it will sufficiently contact with the fins 130 and does not flow away by the gap between the upper margin 131 and the upper casing 200. Therefore, the heat dissipation efficiency can be improved.

According to the above embodiments of the heat exchangers and method for fabricating the heat exchangers, the distance between the upper margin of fins and the bottom surface is substantially gradually reduced along the first direction. The groove extends along the second direction and is formed on the upper margin. As a result, when cutting the fins along the first direction by using a knife, cutting waste is easily removed and does not stuff the passage between fins. Therefore, the heat exchangers and method for fabricating the same not only can avoid blocking passages with cutting waste but also can exactly control the height of fins. Furthermore, small bubbles brought by cooling liquid can be easily removed and thus the heat dissipation efficiency can be improved. 

What is claimed is:
 1. A method for fabricating a heat exchanger, comprising: providing a substrate, the substrate comprising a base portion and a processing portion on the base portion, a thickness of the processing portion being substantially gradually reduced along a first direction, at least one groove being formed on the processing portion, the at least one groove extending along a second direction which intersects with the first direction; skiving a plurality of fins in parallel on the base portion, the plurality of fins extending along the first direction, the groove passing through each fin, each fin having an upper margin far away from the base portion, a distance between each upper margin and the bottom surface being substantially gradually reduced along the first direction; and milling the plurality of fins along the first direction, the maximum distance between the upper margin and a bottom surface of the base portion being smaller than or equal to a preset value.
 2. The method according to claim 1, wherein the first direction is substantially perpendicular to the second direction.
 3. The method according to claim 1, wherein after the step of milling the plurality of fins along the first direction, the method further comprises: providing an upper casing, the upper casing having an accommodating space, a liquid input and a liquid output being connected to the accommodating space, and assembling the upper casing to the base portion, setting the plurality of fins in the accommodating space, the liquid input and the liquid output being disposed at two opposite ends of the plurality of fins.
 4. The method according to claim 3, wherein the upper casing is assembled to the base portion by a solder.
 5. The method according to claim 3, wherein distance between the upper margin near the liquid input and the bottom surface is larger than distance between the upper margin near the liquid output and the bottom surface.
 6. The method according to claim 5, wherein the upper margin near the liquid input is substantially attached to the upper casing.
 7. The method according to claim 1, wherein the step of standing a plurality of fins in parallel on the base portion by milling and curving the processing portion further comprises: cutting the processing portion along a cutting direction which intersects with the upper surface an acute angle so as to form a fin; and bending the fin to stand it on the base portion.
 8. The method according to claim 1, wherein upper margins of the plurality of fins form approximately a broken line.
 9. The method according to claim 1, wherein upper margins of the plurality of fins form approximately an oblique line.
 10. The method according to claim 1, wherein the substrate is fabricated by aluminum extrusion.
 11. A heat exchanger, comprising: a base portion having a bottom surface; and a plurality of fins disposed on a side of the base portion far away from the bottom surface, each fin having an upper margin far away from the base portion, a distance between each upper margin and the bottom surface being substantially gradually reduced along a first direction, the upper margins sunken to form at least one groove, and the groove extending along a second direction which intersects with the first direction.
 12. The heat exchanger according to claim 11, wherein the first direction is substantially perpendicular to the second direction.
 13. The heat exchanger according to claim 11, further comprising an upper casing, the upper casing having an accommodating space, a liquid input a the liquid output being connected to the accommodating space, the upper casing being assembled to the base portion, the fins being set in the accommodating space, the liquid input and the liquid output being disposed at two opposite ends of the plurality of fins.
 14. The heat exchanger according to claim 13, wherein distance between the upper margin near the liquid input and the bottom surface is larger than distance between the upper margin near the liquid output and the bottom surface.
 15. The heat exchanger according to claim 14, wherein the upper margin near the liquid input is substantially attached to the upper casing.
 16. The heat exchanger according to claim 11, wherein upper margins of the plurality of fins form approximately a broken line.
 17. The heat exchanger according to claim 11, wherein the upper margins of the plurality of fins form approximately an oblique line. 